Bipolar electrodialysis based flow battery system

Abstract

A bipolar electrodialysis based flow battery system. Diffusion inhibiting solvents capable of operating at low temperatures are used in conjunction with permeable bipolar membranes that may operate in forward and reverse operation. An ion exchange column is utilized to regenerate stream compositions after operation with non-ideal membranes.

1 . A bipolar electrodialysis flow battery comprising:
 a stack of cells, each cell comprising:
 an acid compartment to contain flow of an acid solution; 
 a base compartment to contain flow of a base solution; and 
 a bipolar membrane disposed between the acid compartment and the base compartment; 
 a salt compartment to contain flow of a salt solution, the salt compartment separated from the acid compartment by an anion exchange membrane or separated from the base compartment by a cation exchange membrane; 
 wherein one or more of the acid compartment, base compartment, and salt compartment contain a solvent having a dielectric constant that is lower than a dielectric constant of water; 
   electrodes positioned at opposite ends of the stack of cells.   
     
     
         2 . The bipolar electrodialysis flow battery of  claim 1 , wherein two or more of the acid compartment, base compartment, and salt compartment contain a solvent having a dielectric constant that is lower than a dielectric constant of water. 
     
     
         3 . The bipolar electrodialysis flow battery of  claim 1 , wherein each of the acid compartment, base compartment, and salt compartment contains a solvent having a dielectric constant that is lower than a dielectric constant of water. 
     
     
         4 . The bipolar electrodialysis flow battery of  claim 1 , wherein the dielectric constant of the solvent is between about 15 and about 80. 
     
     
         5 . The bipolar electrodialysis flow battery of  claim 1 , wherein the dielectric constant of the solvent is between about 60 and about 80. 
     
     
         6 . The bipolar electrodialysis flow battery of  claim 1 , wherein the solvent comprises a mixture of water and a non-water solvent. 
     
     
         7 . The bipolar electrodialysis flow battery of  claim 1 , wherein the solvent comprises a mixture of two or more non-water solvents. 
     
     
         8 . The bipolar electrodialysis flow battery of  claim 1 , wherein the solvent comprises glycol. 
     
     
         9 . The bipolar electrodialysis flow battery of  claim 1 , wherein the solvent comprises alcohol. 
     
     
         10 . The bipolar electrodialysis flow battery of  claim 1 , wherein the solvent comprises one or more of acetone, acetic acid, acetonitrile, ammonia, butanol, ethanol, glycol, ethylene glycol, formic acid, furfural, glycerol, glycerine, isopropanol, methanol, tetrahydrofuran, propanol, propylene glycol, xylitol, polyol, and an alcohol. 
     
     
         11 . The bipolar electrodialysis flow battery of  claim 1 , further comprising an ion exchange column containing ion exchange material, the ion exchange column connected to one of the acid compartment, the base compartment, or the salt compartment to receive flow of a respective one of the acid solution, the base solution, or the salt solution to cause the ion exchange material to restore a concentration of ions in the respective one of the acid solution, the base solution, or the salt solution. 
     
     
         12 . The bipolar electrodialysis flow battery of  claim 1 , further comprising an electrodialysis system including a cation exchange membrane and an anion exchange membrane with flow channels therebetween, wherein the flow channels are connected to two of the acid compartment, the base compartment, or the salt compartment to receive flow of respective two of the acid solution, the base solution, or the salt solution to transfer ions across the cation exchange membrane and the anion exchange membrane to remove unwanted contaminants or restore a concentration of ions in the respective two of the acid solution, the base solution, or the salt solution. 
     
     
         13 . The bipolar electrodialysis flow battery of  claim 1 , further comprising:
 a heat exchanger operable with the acid solution, the base solution, or the salt solution, the heat exchanger configured to:
 extract heat from the solution, wherein the heat is generated by an inefficiency in ohmic ion transport or from a solvent formation reaction occurring at the stack of cells; or 
 provide heat to the solution. 
   
     
     
         14 . The bipolar electrodialysis flow battery of  claim 1 , wherein the bipolar membrane comprises an anion exchange layer, a cation exchange layer, and a solvent permeation layer therebetween, wherein the solvent permeation layer includes ion exchange resin, wherein the anion exchange layer, the cation exchange layer, or the solvent permeation layer are permeable to flow of the solvent. 
     
     
         15 . The bipolar electrodialysis flow battery of  claim 14 , wherein acid solution, base solution, or salt solution in contact with the anion exchange layer or the cation exchange layer alters the permeability of the anion exchange layer or the cation exchange layer. 
     
     
         16 . A bipolar electrodialysis flow battery comprising:
 a stack of cells, each cell comprising:
 an acid compartment to contain flow of an acid solution; 
 a base compartment to contain flow of a base solution; and 
 a bipolar membrane disposed between the acid compartment and the base compartment; 
 a salt compartment to contain flow of a salt solution, the salt compartment separated from the acid compartment by an anion exchange membrane or separated from the base compartment by a cation exchange membrane; 
 wherein one or more of the acid compartment, base compartment, and salt compartment contain a solvent that provides a diffusion coefficient of hydrogen ions or hydroxide ions that is lower than a respective diffusion coefficient of hydrogen ions or hydroxide ions in water; 
   electrodes positioned at opposite ends of the stack of cells.   
     
     
         17 . The bipolar electrodialysis flow battery of  claim 16 , wherein two or more of the acid compartment, base compartment, and salt compartment contain a solvent that provides a diffusion coefficient of hydrogen ions or hydroxide ions that is lower than a respective diffusion coefficient of hydrogen ions or hydroxide ions in water. 
     
     
         18 . The bipolar electrodialysis flow battery of  claim 16 , wherein each of the acid compartment, base compartment, and salt compartment contains a solvent that provides a diffusion coefficient of hydrogen ions or hydroxide ions that is lower than a respective diffusion coefficient of hydrogen ions or hydroxide ions in water. 
     
     
         19 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent provides a diffusion coefficient of hydrogen ions that is less than about 9.3*10 −9  m 2 /s. 
     
     
         20 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent provides a diffusion coefficient of hydrogen ions that is between about 3*10 −9  m 2 /s and about 9.3*10 −9  m 2 /s. 
     
     
         21 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent provides a diffusion coefficient of hydroxide ions that is less than about 5.3*10 −9  m 2 /s. 
     
     
         22 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent provides a diffusion coefficient of hydroxide ions that is between about 2*10 −9  m 2 /s and about 5.3*10 −9  m 2 /s. 
     
     
         23 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent comprises a mixture of water and a non-water solvent. 
     
     
         24 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent comprises a mixture of two or more non-water solvents. 
     
     
         25 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent comprises glycol. 
     
     
         26 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent comprises alcohol. 
     
     
         27 . The bipolar electrodialysis flow battery of  claim 16 , wherein the solvent comprises one or more of acetone, acetic acid, acetonitrile, ammonia, butanol, ethanol, glycol, ethylene glycol, formic acid, furfural, glycerol, glycerine, isopropanol, methanol, tetrahydrofuran, propanol, propylene glycol, xylitol, polyol, and an alcohol. 
     
     
         28 . The bipolar electrodialysis flow battery of  claim 16 , further comprising an ion exchange column containing ion exchange material, the ion exchange column connected to one of the acid compartment, the base compartment, or the salt compartment to receive flow of a respective one of the acid solution, the base solution, or the salt solution to cause the ion exchange material to restore a concentration of ions in the respective one of the acid solution, the base solution, or the salt solution. 
     
     
         29 . The bipolar electrodialysis flow battery of  claim 16 , further comprising an electrodialysis system including a cation exchange membrane and an anion exchange membrane with flow channels therebetween, wherein the flow channels are connected to two of the acid compartment, the base compartment, or the salt compartment to receive flow of respective two of the acid solution, the base solution, or the salt solution to transfer ions across the cation exchange membrane and the anion exchange membrane to remove unwanted contaminants or restore a concentration of ions in the respective two of the acid solution, the base solution, or the salt solution. 
     
     
         30 . The bipolar electrodialysis flow battery of  claim 16 , further comprising:
 a heat exchanger operable with the acid solution, the base solution, or the salt solution, the heat exchanger configured to:
 extract heat from the tank, wherein the heat is generated by an inefficiency in ohmic ion transport or from a solvent formation reaction occurring at the stack of cells; or 
 provide heat to the solution. 
   
     
     
         31 . The bipolar electrodialysis flow battery of  claim 16 , wherein the bipolar membrane comprises an anion exchange layer, a cation exchange layer, and a solvent permeation layer therebetween, wherein the solvent permeation layer includes ion exchange resin, wherein the anion exchange layer, the cation exchange layer, or the solvent permeation layer are permeable to flow of the solvent. 
     
     
         32 . The bipolar electrodialysis flow battery of  claim 31 , wherein acid solution, base solution, or salt solution in contact with the anion exchange layer or the cation exchange layer alters the permeability of the anion exchange layer or the cation exchange layer.